Collagen for Hair Growth: Does It Work & Is It Safe

Collagen for hair growth has some early trial support for thicker and healthier-looking strands, but no trial shows that it treats hair loss or regrows hair. The best results so far come from small, mostly industry-funded studies of specific collagen peptide products.

So, can collagen help hair growth? It may help the hair you already have look and feel better, but it has not been shown to restore hair lost to pattern baldness, hormones or illness. This guide explains what each trial measured, which collagen types were tested, what the side effects and limits are, and when a doctor is a better first step than a supplement.

What Collagen Is Best for Hair Growth?

No collagen has been shown to be best for hair growth, because no trial has compared types head to head. A 2026 review in Nutrients concluded that results were most consistent with low-molecular-weight peptides rich in hydroxyproline, and that the peptide characteristics seemed to matter more than the animal source.

In practice, the trials with hair results used hydrolysed collagen, which is collagen broken down into smaller pieces called peptides. Plain gelatin and collagen in food were not what these studies tested.

What Collagen Is Good for Hair Growth?

Hydrolysed collagen peptides are the form used in the hair trials. Look for a product that states its collagen type, source and peptide size on the label.

What Collagen Is Best for Hair Growth and Skin?

Most collagen trials measured skin first and hair second. A 2019 review of 11 trials found benefits for skin elasticity and hydration; hair was not among the measured results.

Which Collagen Type Is Best for Hair Growth?

Labels often list type I, II or III collagen, or marine, bovine and chicken sources. The hair trials do not show that one type wins:

• Fish collagen peptides: used in two 2026 trials that measured thicker hair strands.
• Hydrolysed collagen with vitamin C: used in a 2024 trial that measured hair count.
• Collagen mixed with biotin, hyaluronic acid and vitamins: used in a 2024 trial that measured hair fall.
• Type I, II or III labels: we found no trial comparing them for hair.

Marine collagen benefits for hair growth are often claimed, and the two fish peptide trials did report thicker strands. But these trials tested specific processed ingredients, so their results do not automatically transfer to every marine collagen powder on the shelf.

Can Collagen Cause Hair Growth?

There is no trial showing that collagen causes new hair to grow in people with hair loss. The most direct test is a 2024 trial in 140 adults aged 40 to 60, most of them women, who took a hydrolysed collagen sachet with vitamin C or a placebo. After 12 weeks, the total number of hairs counted was 27.6% higher than with placebo, but the difference was not statistically significant. Expert grading of how healthy the hair looked did improve significantly. The study was funded by the company that makes the product.

In a 2026 trial, 114 women with self-reported hair thinning took fish collagen peptides or a placebo for 24 weeks. Hair diameter increased significantly at week 24. Thicker strands can make hair look fuller, but this is not the same as more hairs on the scalp.

Collagen Hair Loss Treatment

Collagen is not an approved hair loss treatment. Pattern hair loss is driven by the hormone DHT, explained in our DHT and hair loss guide, and only finasteride and minoxidil are FDA-approved for it, according to a 2024 review. The American Academy of Dermatology lists iron deficiency, thyroid disease, stress and childbirth among common causes of hair loss, and each needs its cause treated first. After pregnancy, our postpartum hair loss guide explains what to expect.

When people search for the best collagen treatment for hair growth and thickness, what they usually find are supplement products. Under US law, the FDA does not approve dietary supplements for safety or effectiveness before they are sold, so a label claim is not proof. If you are unsure why your hair is thinning, read our guide to the reasons for hair loss or see a dermatologist.

Does Collagen for Hair Growth Work?

The honest answer is: partly, for hair quality, and not shown for hair loss. Here is what the main trials found:

The collagen for hair growth benefits reported in these trials are mostly about the strand itself. Collagen benefits for hair growth and thickness are more convincing for thickness than for growth.

How Effective Is Collagen for Hair Growth?

The effect is modest and not yet proven by independent research. The 2026 review notes that short study times, mixed-ingredient products and industry funding reduce confidence in the size of the effects. For collagen shampoo benefits for hair growth, we found no published trial at all.

Risk of Collagen Supplements

A 2019 systematic review found collagen supplementation generally safe, with no adverse events reported in the 11 trials it included. A 2026 trial in damaged hair also reported no treatment-related adverse events. Collagen for hair growth side effects are therefore uncommon in trials, but trials are short and use controlled products.

Practical risks to keep in mind:

• Check the source on the label if you have a food allergy.
• Many products add biotin, vitamins or herbs, each with its own effects.
• Some products marketed as a collagen superdose for hair growth have no published trial, so their side effects are unknown.
• Supplements are not checked by the FDA for safety before sale.

Ask your doctor before taking collagen or any hair supplement if you are pregnant or breastfeeding, have a medical condition or take medicines. Sudden shedding, patchy hair loss or a sore, scaly scalp should be checked by a dermatologist rather than treated with a supplement.

Frequently Asked Questions

Is Your Hair Still Thinning?

If you have tried supplements for months and your hairline or crown is still thinning, the pattern of loss tells more than another product. Send clear photos for a free hair analysis, and the medical team will tell you what they see. Women can also read about hair transplant for women and who is a candidate.

Medical disclaimer: This article is for informational purposes only and is not medical advice. Individual results and recovery vary from person to person. Always follow the written aftercare plan from your own medical team.