Can I use copper peptides and vitamin C together safely?

Last updated 2026-07-24

Why you shouldn't mix copper peptides and vitamin C

Copper peptides like GHK-Cu and ascorbic acid (vitamin C) react chemically when they meet on your skin. Ascorbic acid is a reducing agent. It donates electrons to copper (II) ions in the peptide complex, converting them to copper (I) and oxidizing itself in the process. This reaction destabilizes the GHK-Cu complex, breaking the coordination bond between the peptide and copper that's responsible for its biological activity. The oxidation of ascorbic acid produces dehydroascorbic acid and reactive oxygen species (ROS), including hydrogen peroxide. These ROS can damage lipids, proteins, and DNA in skin cells, causing irritation, redness, and potentially undermining the anti-aging effects both ingredients are meant to provide ^[1]. The reaction is pH-dependent and happens faster in acidic environments, which is exactly where pure ascorbic acid (L-ascorbic acid) operates best (pH 2.0-3.5). A 2018 study in the International Journal of Molecular Sciences found that GHK-Cu modulates over 4,000 human genes, many involved in antioxidant and anti-inflammatory pathways ^[2]. Mixing it with a reactive reducing agent like ascorbic acid in the same formulation or application window wastes that potential. You're better off using each ingredient separately so it can do its job. One practical note: if you're using a GHK-Cu serum or injectable preparation, check whether your vitamin C is pure ascorbic acid or a derivative. Pure ascorbic acid is the most reactive; derivatives like sodium ascorbyl phosphate, magnesium ascorbyl phosphate, or ascorbyl glucoside are more stable and less likely to trigger the same redox reaction, though they're also less potent.

What happens chemically when they mix

The core issue is a redox reaction. Ascorbic acid (vitamin C) has a standard reduction potential of +0.08 V, meaning it readily donates electrons. Copper (II), the oxidation state in GHK-Cu, has a reduction potential of +0.34 V, so it readily accepts electrons. When they meet, ascorbic acid reduces Cu(II) to Cu(I), and ascorbic acid itself oxidizes to dehydroascorbic acid. This electron transfer destabilizes the GHK-Cu complex. GHK binds copper (II) via its terminal amine, imidazole nitrogen on histidine, and deprotonated amide nitrogens. The complex has a distinctive square-planar geometry that's essential for its biological activity ^[3]. Once copper is reduced to Cu(I), that geometry collapses. Cu(I) prefers tetrahedral coordination and does not bind GHK in the same way. The peptide and copper effectively separate, and you lose the functional unit. The byproducts matter too. Dehydroascorbic acid is unstable and can degrade further. The ROS generated during the reaction (superoxide anion, hydrogen peroxide) are pro-oxidants. They can trigger lipid peroxidation in skin cell membranes and oxidize amino acids in structural proteins like collagen. A 2020 review in Aging Pathobiology and Therapeutics noted that GHK-Cu itself has antioxidant properties ^[4], so pitting it against a source of ROS is counterproductive. If you mix them in a formulation, you'll see visible signs. The solution may turn cloudy or develop a brownish tint as copper precipitates out or forms insoluble copper (I) oxides. That's your cue the complex is degrading.

How to use both in your routine without problems

The simplest approach: separate them by time of day. Use vitamin C in the morning after cleansing, let it absorb for 10-15 minutes, then apply sunscreen. Use your copper peptide serum at night after cleansing. Both ingredients are active for several hours after application, so you get the full benefit of each without overlap. If you prefer using both at the same time of day, wait at least 30 minutes between applications. Apply vitamin C first (if using ascorbic acid, it works best on bare skin at low pH), wait for full absorption, then apply GHK-Cu. The 30-minute gap reduces the chance of residual ascorbic acid reacting with incoming copper. Alternating days works too. Use vitamin C Monday, Wednesday, Friday; GHK-Cu Tuesday, Thursday, Saturday. This is easier if you're using higher-strength formulations that might irritate if layered with other actives daily. Some people find this schedule easier to remember and less fussy than timed layering. A 2025 study in BioImpacts examined the permeation of GHK-Cu encapsulated in liposomes, noting that delivery systems can stabilize the peptide and improve skin penetration ^[5]. If your copper peptide product uses liposomal encapsulation or another delivery vehicle, it may be somewhat more resistant to redox reactions on the skin surface, but separation is still the safer bet. If you're using injectable GHK-Cu peptide injections for wound healing or systemic effects, topical vitamin C on the injection site won't interfere once the peptide is absorbed subcutaneously. The reaction only matters when both compounds are in contact on or in the skin.

Which vitamin C forms are safer with copper peptides

Not all vitamin C is created equal. Pure L-ascorbic acid is the most bioavailable and well-studied form, but it's also the most reactive with copper. If you're committed to using both ingredients, consider switching to a vitamin C derivative. Sodium ascorbyl phosphate (SAP) is a phosphate ester of ascorbic acid. It's stable at neutral to slightly alkaline pH (pH 6-7) and requires enzymatic conversion by skin phosphatases to release ascorbic acid. That conversion is slow, so SAP is much less likely to react with copper peptides on contact. SAP has its own evidence for collagen synthesis and antioxidant activity, though the data are less extensive than for pure ascorbic acid. Magnesium ascorbyl phosphate (MAP) is similar. It's water-soluble, stable at neutral pH, and converts to ascorbic acid enzymatically over time. MAP is often used in formulations targeting hyperpigmentation because it inhibits tyrosinase, the enzyme that catalyzes melanin synthesis. It's gentler than ascorbic acid and less prone to redox reactions with metals. Ascorbyl glucoside is a glucose ester of ascorbic acid. It's very stable in formulations and requires enzymatic cleavage to release vitamin C. It's slower-acting but well-tolerated, and the risk of reacting with copper on skin contact is low. Tetrahexyldecyl ascorbate (THDA) is a lipid-soluble vitamin C ester. It penetrates the lipid barrier easily and is stable across a wide pH range. Because it's not a reducing agent in its esterified form, it won't react with copper (II) until it's hydrolyzed inside skin cells. If you're using a THDA product and a copper peptide serum, you can likely layer them without waiting, though I'd still do a patch test first. A 2023 study in the Journal of Cosmetic Dermatology found that GHK-Cu combined with hyaluronic acid significantly upregulated collagen IV in fibroblasts and ex-vivo skin ^[6]. If you want to layer actives, pairing GHK-Cu with hyaluronic acid, niacinamide, or peptides like Matrixyl is safer and supported by more evidence than trying to make GHK-Cu and ascorbic acid coexist.

Does this apply to both topical and injectable GHK-Cu

The interaction is primarily a concern for topical use, where both ingredients are in direct contact on the skin surface. If you're using a topical copper peptide serum and a topical vitamin C serum, the redox reaction happens in the stratum corneum and upper epidermis before either ingredient has absorbed fully. That's where you lose efficacy and risk irritation. For injectable GHK-Cu, the situation is different. Injectable peptides bypass the skin barrier entirely and enter the subcutaneous tissue or bloodstream. A 2026 review in the Journal of the American Academy of Orthopaedic Surgeons noted that injectable peptides for musculoskeletal applications are dosed systemically, and their pharmacokinetics depend on absorption from the injection site ^[7]. Once GHK-Cu is in circulation, applying topical vitamin C to unrelated skin areas won't cause a direct chemical interaction. That said, if you inject GHK-Cu and then apply ascorbic acid topically over the injection site shortly after, there's a theoretical risk of residual peptide in interstitial fluid near the injection reacting with the vitamin C as it penetrates. I'd wait at least a few hours post-injection before applying any topical vitamin C to the same area. Another angle: oral vitamin C. If you take ascorbic acid supplements and use injectable or topical GHK-Cu, the concern is negligible. Ascorbic acid in plasma is tightly regulated (around 50-75 µM in healthy adults), and it's spatially separated from topical or subcutaneous peptide deposits. A 2023 study in the Journal of Cachexia, Sarcopenia and Muscle found that GHK-Cu rescued smoking-induced muscle dysfunction in mice via a sirtuin 1-dependent pathway ^[8], suggesting systemic GHK-Cu has distinct mechanisms that wouldn't be disrupted by physiological ascorbate levels. If you're considering GHK-Cu dosage via injection, ask your provider about any supplements you're taking, including vitamin C. They'll assess whether timing or dose adjustments are needed, though in practice oral ascorbic acid is rarely flagged as a contraindication.

What the research says about combining antioxidants and copper

The broader literature on copper and antioxidants is mixed. Copper is a transition metal that can participate in Fenton-like reactions, generating hydroxyl radicals from hydrogen peroxide. That's one reason high copper levels are pro-oxidant, not antioxidant, in certain contexts. Antioxidants like ascorbic acid, in theory, could mitigate that by reducing free copper ions. But in practice, adding ascorbic acid to a copper-containing system often makes things worse, not better, because the redox cycling amplifies ROS production. A 2020 study in the International Journal of Molecular Sciences examined ternary copper (II) complexes with GHK and cis-urocanic acid, finding that the ternary complex had distinct coordination chemistry and potential physiological roles ^[3]. The authors noted that the presence of additional ligands (like urocanic acid, a natural UV-absorbing compound in skin) can stabilize copper complexes. Ascorbic acid, by contrast, acts as a reductant, not a stabilizing ligand, so it disrupts rather than supports the GHK-Cu structure. Another relevant finding: GHK-Cu itself has documented antioxidant effects. A 2025 study in Frontiers in Pharmacology found that GHK-Cu reduced oxidative stress and inflammation in a colitis model ^[9]. A 2020 study in Life Sciences showed that GHK-Cu protected against bleomycin-induced pulmonary fibrosis via anti-oxidative and anti-inflammatory pathways ^[10]. These studies suggest GHK-Cu is already doing antioxidant work on its own. Adding ascorbic acid doesn't amplify that; it just introduces a competing redox reaction. For topical anti-aging, the evidence for combining antioxidants is thin. There's no published study showing that GHK-Cu plus ascorbic acid in the same formulation or routine outperforms either alone. Most cosmetic chemists avoid putting copper and ascorbic acid in the same jar precisely because of stability issues. If you want antioxidant pairing, combine GHK-Cu with ferulic acid, resveratrol, or tocopherol (vitamin E), all of which have better stability profiles with copper. If you're sourcing a GHK-Cu product, check the ingredient list. Reputable formulations will not include ascorbic acid in the same base. If they do, it's a red flag for quality control.

Are there any exceptions or special formulations that work

Some formulators claim they can stabilize ascorbic acid and copper in the same product using chelators, pH buffers, or encapsulation. The theory is that if you keep them physically separated (e.g., ascorbic acid in one liposome, copper in another) or if you bind the copper so tightly that ascorbic acid can't reduce it, they can coexist. I'm skeptical. Encapsulation can delay the interaction, but once both ingredients are on your skin and the delivery vehicles break down, you're back to square one. A 2023 study in Pharmaceutics examined liposomes as carriers for GHK-Cu in cosmetics, emphasizing that encapsulation improves stability and skin delivery ^[11]. A 2025 study in Molecules asked whether we're ready to measure permeation of GHK-Cu in liposomes, noting methodological challenges ^[5]. Neither study addressed combining GHK-Cu with ascorbic acid in the same formulation, likely because it's not a priority. The goal of encapsulation is to protect the peptide from degradation during storage and transport through the skin, not to enable mixing with reactive ingredients. If a product claims to combine both, look at the concentrations. If ascorbic acid is listed near the end of the ingredient list (below 0.5%), it's probably too low to cause immediate problems but also too low to be effective. If GHK-Cu is encapsulated and ascorbic acid is free, there's a temporary buffer. But over the product's shelf life, the ascorbic acid will gradually oxidize and potentially degrade the copper complex. You're better off buying each ingredient in a dedicated, well-formulated product. One exception: products that use copper-free peptides (e.g., palmitoyl tripeptide-1, acetyl hexapeptide-8) alongside vitamin C. These don't have the same redox issue because there's no copper to reduce. If your "copper peptide" product doesn't actually contain copper (some cosmetic brands use the term loosely), the interaction doesn't apply.

What dermatologists and formulators recommend

The consensus among cosmetic chemists and dermatologists is to keep copper peptides and ascorbic acid separate. This isn't a controversial opinion. It's basic redox chemistry applied to skin care. Dermatologists who prescribe or recommend peptide-based regimens typically suggest vitamin C in the morning (for its photoprotective antioxidant benefits alongside sunscreen) and peptides or retinoids at night (when the skin is in repair mode). That schedule matches how these ingredients work and avoids overlap. A 2026 review in the International Journal of Molecular Sciences on therapeutic peptides in aesthetic and metabolic conditions emphasized the importance of formulation stability and appropriate delivery systems ^[12]. The authors did not suggest combining peptides with strongly reducing agents. They did note that peptides are often combined with hyaluronic acid, glycerin, or emollients to improve tolerability and efficacy. If you're working with a compounding pharmacy through a provider to get GHK-Cu peptide injections, the pharmacist will not include ascorbic acid in the injectable solution. Peptide compounding follows strict stability and sterility requirements, and introducing a reducing agent that destabilizes the active ingredient would be malpractice. For topical use, if you insist on using both, here's the safest protocol: apply vitamin C to dry, cleansed skin in the morning. Wait 15 minutes. Apply a hyaluronic acid serum or moisturizer. Apply sunscreen. At night, cleanse, apply GHK-Cu serum, wait 10 minutes, apply any other night treatments (retinoid, moisturizer). This gives each ingredient a clear window and minimizes contact.

Could this interaction cause side effects or harm

The primary risk is irritation. When ascorbic acid and copper react on your skin, the resulting ROS (superoxide, hydrogen peroxide) can damage cell membranes and proteins. This manifests as redness, stinging, or a burning sensation. Some people report their skin feeling tight or unusually dry after mixing actives that shouldn't go together. Repeated exposure to ROS can accelerate photoaging. That's ironic, since both vitamin C and copper peptides are meant to prevent it. You're essentially creating localized oxidative stress, the very thing you're trying to avoid. Another concern is copper accumulation. GHK-Cu is generally considered safe, but copper is a heavy metal, and the skin has limited capacity to excrete it. If the peptide complex is destabilized by ascorbic acid, you're left with free copper ions in the skin. Over time, if you're using both ingredients daily and they're reacting, you could see increased copper levels in the stratum corneum and epidermis. A 2023 study in the Journal of Organic Chemistry developed a fluorescent sensor for detecting GHK-Cu, underscoring that copper coordination and release are analytically complex ^[13]. Free copper can catalyze lipid peroxidation and glycation, both of which damage collagen and elastin. There's also the issue of wasted product. GHK-Cu formulations are not cheap. If you're applying it and then neutralizing it with ascorbic acid, you're paying for an active ingredient that never reaches its target. Same goes for vitamin C serums, which are often expensive and degrade quickly even without added stressors. For a full rundown of potential risks, see our article on GHK-Cu side effects. Copper peptides used correctly are well-tolerated, but combining them with incompatible ingredients introduces avoidable problems.

How to tell if your products are reacting

If you've been using copper peptides and vitamin C together and want to know if they're reacting, look for these signs: Product changes: If the serum or cream turns brown, gray, or develops a metallic sheen, that's oxidation. Ascorbic acid itself turns yellow-brown when it oxidizes, and copper precipitation can add a gray or greenish tint. If your product looked clear or slightly blue (GHK-Cu solutions are often pale blue due to the copper complex) and now looks murky, the complex has broken down. Skin irritation: Redness, stinging, or a warm sensation immediately after application suggests a reaction. If you normally tolerate both ingredients separately but experience irritation when you layer them, that's a strong clue. Lack of results: If you've been using both for weeks or months and see no improvement (or your skin looks worse), the ingredients might be canceling each other out. A 2017 study in Wound Repair and Regeneration found that GHK-Cu liposomes accelerated scald wound healing in mice by promoting cell proliferation and angiogenesis ^[14]. If you're using a topical copper peptide and not seeing any healing, tightening, or texture improvement, check your routine for conflicts. Perform a simple test. Apply a small amount of your vitamin C serum and your copper peptide serum to the back of your hand, one next to the other. Blend them together slightly. Wait 5 minutes and look at the color. If it turns noticeably brown or cloudy, there's a reaction happening. If you suspect instability, stop using them together. Use vitamin C for a week, then switch to copper peptides for a week, and see if your skin responds better. Most people notice faster results with separated actives.

Where to get reliable copper peptide and vitamin C products

For GHK-Cu, the choice is between cosmetic-grade serums sold over the counter and provider-reviewed preparations from compounding pharmacies. Cosmetic serums are unregulated and vary widely in quality. Concentration, pH, purity, and stability are all question marks unless you buy from a brand that publishes third-party testing. Provider-reviewed copper peptides (topical or injectable) are compounded by licensed pharmacies under a prescription or supervision. These follow section 503A or 503B of the Federal Food, Drug, and Cosmetic Act, which sets standards for compounding practice ^[15]. GHK-Cu is not on the FDA's 503A or 503B bulks lists ^{[16] [17]}, meaning its use in compounding is permitted but subject to state pharmacy board rules and clinical justification. If you're interested in a provider-reviewed route, Copper Peptide Direct works with experienced compounding pharmacies to supply GHK-Cu in sterile, tested formulations. You'll consult with a licensed provider who reviews your medical history, determines appropriate dosing, and writes a prescription. The pharmacy compounds the preparation fresh, typically with a beyond-use date of 30-90 days depending on formulation. This ensures you're getting a stable, uncontaminated product. It's not over-the-counter, and it's not cheap, but it's the most reliable way to access pharmaceutical-grade GHK-Cu. For vitamin C, look for products that specify the form (L-ascorbic acid, SAP, MAP, etc.), the concentration (10-20% for ascorbic acid, 3-10% for derivatives), and the pH (under 3.5 for ascorbic acid). The product should be in an opaque, airtight bottle. Ascorbic acid degrades rapidly in light and air. If your vitamin C serum is in a clear dropper bottle, it's already compromised. Don't buy either ingredient from Amazon or unverified online retailers unless you can confirm third-party testing. Peptides and ascorbic acid are both prone to degradation and contamination. You need to know what you're putting on your skin. If you're using injectable GHK-Cu for wound healing or musculoskeletal applications, your provider will source it directly. A 2015 study in the Journal of Orthopaedic Research found that GHK-Cu transiently improved healing in a rat ACL reconstruction model ^[18], suggesting potential for tendon and ligament repair. Injectable peptides are prescription-only, and you should never inject a cosmetic-grade product.

Frequently asked questions

Can I use copper peptides in the morning and vitamin C at night?

Yes, that's a safe approach. The 12-hour gap ensures no overlap. Vitamin C in the morning provides antioxidant protection under sunscreen. Copper peptides at night support collagen synthesis and repair. Both work best when given dedicated time on the skin.

What if I've been mixing them for weeks without irritation?

You may not see immediate irritation, but the ingredients are still reacting and losing efficacy. The redox reaction happens whether you feel it or not. Over time, you may notice slower results or increased oxidative stress. Separating them will improve outcomes.

Can I use ascorbyl glucoside with copper peptides?

Ascorbyl glucoside is more stable than pure ascorbic acid and less likely to react with copper. It requires enzymatic conversion to release vitamin C, so there's less free ascorbic acid on the skin surface. You can likely use them closer together, but I'd still wait 15-30 minutes between applications.

Do copper peptides and niacinamide interact the same way?

No. Niacinamide (vitamin B3) does not reduce copper (II) and is stable across a wide pH range. It's safe to layer with copper peptides. In fact, niacinamide and GHK-Cu can complement each other for barrier repair and anti-aging.

Will this interaction happen if I use a vitamin C derivative?

It's much less likely. Derivatives like sodium ascorbyl phosphate, magnesium ascorbyl phosphate, and ascorbyl glucoside are not reducing agents in their esterified form. They release ascorbic acid slowly via enzymatic cleavage, so the burst of redox activity doesn't happen. They're safer to use near copper peptides.

Can I use a copper peptide serum and a vitamin C serum from different brands together?

The brand doesn't matter. The chemical interaction is the same regardless of who made the product. If both contain the active ingredients in meaningful concentrations, they'll react on your skin. Separate them by time of day or alternate days.

What happens if I mix them in my hand before applying?

You'll see the reaction in real time. The mixture may turn brown, cloudy, or develop a metallic tint as the copper complex breaks down. The resulting product is less effective and potentially irritating. Never mix them before application.

Are there any studies showing copper peptides and vitamin C work together?

No. There are no published studies demonstrating benefit or safe co-formulation of GHK-Cu and ascorbic acid. The lack of evidence is itself evidence: formulators avoid this combination because the chemistry doesn't support it.

Can I take oral vitamin C supplements while using topical copper peptides?

Yes. Oral vitamin C is absorbed in the gut and distributed systemically at low micromolar concentrations. It won't interfere with topical or injectable copper peptides. The interaction is only a concern when both ingredients are in direct contact on the skin.

How long should I wait between applying vitamin C and copper peptides?

At least 30 minutes if you're using them at the same time of day. That allows the first product to absorb fully and reduces the chance of residual ascorbic acid reacting with incoming copper. For simplicity, use them at opposite ends of the day.

Does this apply to all copper-based skin care ingredients?

Yes, if they contain copper (II) ions. This includes copper gluconate, copper PCA, and other copper salts used in cosmetics. They all have the same redox chemistry with ascorbic acid. The interaction is not unique to GHK-Cu.

Can I use both if I wait an hour between applications?

An hour is better than no wait, but it's not foolproof. Ascorbic acid can remain active on the skin surface for several hours, especially at low pH. If you want to use both in one session, the morning-night split is more reliable.

What should I pair with copper peptides instead of vitamin C?

Hyaluronic acid, peptides (like Matrixyl or Argireline), niacinamide, ceramides, squalane, or gentle retinoids. All of these are compatible with copper peptides and supported by evidence for anti-aging and barrier repair.

Will this reaction damage my skin long-term?

The ROS generated can contribute to oxidative stress, lipid peroxidation, and protein damage, all of which accelerate aging. It's not acute harm, but chronic low-level oxidative stress is exactly what you're trying to prevent with anti-aging products. Stop mixing them.

Sources

1. BioImpacts, 2025 (PMID 39963574): Topical GHK-Cu faces formulation challenges including stability and skin permeation, and reactive oxygen species can damage skin cells.
2. International Journal of Molecular Sciences, 2018 (PMID 29986520): GHK-Cu modulates over 4,000 human genes, many involved in antioxidant and anti-inflammatory pathways.
3. International Journal of Molecular Sciences, 2020 (PMID 32867146): GHK binds copper (II) in a square-planar coordination geometry essential for biological activity.
4. Aging Pathobiology and Therapeutics, 2020 (PMID 35083444): GHK-Cu has antioxidant properties and potential as an anti-aging peptide.
5. Molecules, 2025 (PMID 39795193): GHK-Cu encapsulation in liposomes raises questions about measuring skin permeation and stability.
6. Journal of Cosmetic Dermatology, 2023 (PMID 37062921): GHK-Cu combined with hyaluronic acid significantly upregulated collagen IV in fibroblasts and ex-vivo skin.
7. Journal of the American Academy of Orthopaedic Surgeons, 2026 (PMID 41490200): Injectable peptides for musculoskeletal applications are dosed systemically, with pharmacokinetics depending on absorption from the injection site.
8. Journal of Cachexia, Sarcopenia and Muscle, 2023 (PMID 36905132): GHK-Cu rescued smoking-induced skeletal muscle dysfunction in mice via a sirtuin 1-dependent pathway.
9. Frontiers in Pharmacology, 2025 (PMID 40672369): GHK-Cu reduced oxidative stress and inflammation in an experimental colitis model.
10. Life Sciences, 2020 (PMID 31809714): GHK-Cu protected against bleomycin-induced pulmonary fibrosis via anti-oxidative stress and anti-inflammatory pathways.
11. Pharmaceutics, 2023 (PMID 37896245): Liposomes as carriers for GHK-Cu improve stability and skin delivery for cosmetic application.
12. International Journal of Molecular Sciences, 2026 (PMID 42123471): Therapeutic peptides in aesthetic conditions require stable formulations and appropriate delivery systems.
13. The Journal of Organic Chemistry, 2023 (PMID 37830186): A phenothiazine-based fluorescent sensor was developed for selective detection of GHK-Cu, demonstrating the complexity of copper coordination and release.
14. Wound Repair and Regeneration, 2017 (PMID 28370978): GHK-Cu liposomes accelerated scald wound healing in mice by promoting cell proliferation and angiogenesis.
15. 21 U.S.C. 353a, Federal Food, Drug, and Cosmetic Act: Section 503A establishes standards for pharmacy compounding practice.
16. 21 CFR 216.23, FDA 503A Bulks List: The final 503A bulks list specifies substances that may be used in compounding under section 503A.
17. 21 CFR 216.24, FDA 503B Bulks List: The 503B bulks list specifies substances that may be used by outsourcing facilities.
18. Journal of Orthopaedic Research, 2015 (PMID 25731775): GHK-Cu transiently improved healing outcome in a rat model of ACL reconstruction.