How to Increase Collagen: Distinguishing the Evidence

Methods for increasing collagen range from ingestible products to prescription medicines and procedures, and the key to choosing is whether the change you want has been confirmed in people. As age and ultraviolet exposure accumulate, skin collagen breaks down faster and the capacity to make new collagen weakens. Ingestion, topical use, and procedures, however, differ in what has been confirmed and how far those findings apply.

3-line summary

Oral collagen has been studied in people for changes in hydration, wrinkles, and elasticity.
Prescription tretinoin and energy-based procedures have also been confirmed in people, but the outcomes measured differ, so their effects cannot readily be compared as numbers.
Evidence on collagen synthesis with injectable polynucleotide (PN) comes from cell and animal studies, and vitamin C is involved in the synthesis process.

Why collagen decreases

As skin ages and ultraviolet exposure accumulates, existing collagen is broken down faster and less new collagen is made. In collagen care, it is therefore more realistic to look at ultraviolet exposure, skin condition, and the change you want together, rather than at the name of a single ingredient.

Confirmed results differ by method

Even the same claim that “collagen increased” carries different weight depending on whether it was seen in cells on a dish, used in animals, or applied and measured in people. The representative evidence in the table below shows that difference.

Method	Representative evidence	What has been confirmed	Outside the confirmed scope
Oral collagen	2 analyses pooling human studies	Hydration improved consistently; wrinkle and elasticity changes were also reported	A direct increase in total skin collagen, and the same effect from every product
Prescription tretinoin	Comparative human studies and a review pooling studies	Used in photoaging treatment; the degree of irritation can vary with concentration	The conclusion that higher concentration means greater effect
Radiofrequency	A review pooling multiple human studies	New collagen formation reported on skin histology	Ranking versus other methods
Microfocused ultrasound (MFU)	A review pooling multiple human studies	Changes reported in brow elevation distance and in investigator and patient assessments	Large-magnitude lift and agreement among raters
Injectable PN	Cell and animal studies	A process that promotes collagen synthesis via immune cells was observed	Effect size and duration in human skin
Vitamin C	Evidence on the process by which collagen is made	Involved in collagen synthesis	Effects of specific foods, supplements, or cosmetics

※ Hydration, wrinkles, histology, and lift are different outcomes. You can use a finding to inform a choice only when the change you want matches what the study measured.

Where to start

Desired change	Check first	Points to watch
Hydration, fine lines, elasticity	Ingredients and dose used in the oral product	Confirm that the product you chose matches the study product
Photoaging care	Concentration and frequency of prescription tretinoin	Confirm skin condition and irritation risk in a medical visit
Tissue change, lift	Outcomes measured for radiofrequency and microfocused ultrasound	Do not compare different outcomes as a single number
Injectable PN	Whether findings were confirmed in people	Do not read cell and animal synthesis results as the size of effect in people

Oral collagen

Match the ingredient and dose used in studies against the product label, rather than the wording on the front of the pack. Studies were generally small, with many female participants, and some were industry-funded. Even under the same collagen product category, if the ingredient and dose differ, study results are hard to apply as they stand.

Topical prescription tretinoin

Tretinoin is a vitamin A–class ingredient prescribed in Korea after a dermatology visit. After reviewing skin condition and irritation risk, concentration and application frequency are set. A higher concentration does not by itself mean a greater effect, and irritation can differ by concentration.

Radiofrequency and microfocused ultrasound

Radiofrequency has mainly been examined for changes in skin tissue, and microfocused ultrasound for lift distance and investigator and patient assessments. Because the measurement criteria differ, the two methods should be viewed against the change you want rather than lined up by study numbers alone. Principles of microfocused ultrasound and information on the actual procedure can be read further in the Ulthera guide.

Injectable PN

Data on PN collagen synthesis were observed in cells and animals. How much change occurs in human skin and how long it lasts should be judged from separate human data. What PN is as an ingredient is in the Rejuran Healer guide; the procedure and recovery are in the Rejuran information.

Selection checklist

Filling in the items below from the top makes it easier to separate advertising copy from actual evidence.

• □ Decide on one desired change — Set a priority among hydration, fine lines, pigment, elasticity, and lift.
• □ See what the study measured — Confirm whether it was histology, device measurement, photographic assessment, or self-assessment.
• □ Check that the product, ingredient, or device used in the study matches the method you are considering.
• □ Distinguish the time point when change was measured from the duration after treatment ended.
• □ For prescription medicines and procedures, review contraindications, adverse effects, and recovery plans together with the treatment safety information.

Frequently asked questions

Q1. Does oral collagen work?

In analyses pooling human studies, improvement in skin hydration was reported fairly consistently, and wrinkle and elasticity changes were also observed. Because the ingredient and dose used in studies differ by product, they should be matched against the actual product label and study conditions rather than used as a basis for expecting the same result from every collagen product.

Q2. Which should I start with, a topical product or a procedure?

First distinguish whether the change you want is photoaging care, or tissue change and lift. Tretinoin is a prescription medicine whose concentration and frequency are set after a medical visit, and radiofrequency and microfocused ultrasound are procedures that have examined tissue change and lift in different ways. Set the order while also considering skin condition and a recovery plan.

Q3. Is tretinoin better at a higher concentration?

In a comparative human study, efficacy was the same at different concentrations, but irritation differed. Concentration and frequency are adjusted in a visit that reviews skin condition, rather than decided by product choice alone.

Q4. How much lift does microfocused ultrasound produce?

Studies directly measured the distance the brow was raised and also recorded investigator and patient assessments. Results differed by assessment method and did not support a large-magnitude lift. Specific treatment areas and the process can be confirmed in the Ulthera guide.

Q5. Does a PN injection increase collagen?

In cell and animal studies, a process that promoted collagen synthesis was observed. This material should be distinguished from data that directly show effect size or duration in human skin. The ingredient and procedure can be read further in the Rejuran Healer guide and the Rejuran information.

Results, duration, and suitability vary with individual skin condition, age, and lifestyle, and the same outcome cannot be guaranteed.

Procedures may cause temporary redness or swelling, and contraindications may apply, so please confirm these during your consultation.

This article is general information and does not replace individual medical care. Please confirm diagnosis and treatment suited to your condition during a consultation.

Sources

• International Journal of Molecular Sciences: review of skin aging and collagen-loss mechanisms — explanation of increased MMP activity and ROS-related TGF-β signaling impairment in the “Why collagen decreases” section
• 2 oral collagen meta-analyses — analysis of 19 studies and 1,125 people in International Journal of Dermatology(2021) and analysis of 26 randomized controlled trials and 1,721 people in Nutrients(2023). In the latter, hydration improvement was statistically significant and there was no statistically clear difference in the elasticity effect among subgroups
• 2 tretinoin sources — in a 48-week randomized controlled trial (99 people), 0.1% and 0.025% had the same efficacy with a difference in irritation, and the American Journal of Clinical Dermatology systematic review (2024) evaluated it as standard treatment for photoaging
• 2 systematic reviews of energy-based procedures — a radiofrequency review of 121 papers reported new collagen formation on histology. A microfocused ultrasound review reported brow lift of 0.47~1.7mm, investigator-rated improvement 92%, and patient self-rated improvement 42%
• Preclinical study of macrophage-mediated collagen synthesis with injectable polynucleotide — a 2025 cell and animal study, the basis for the PN row in the table

Related reading

• Skin elasticity treatment guide
• Skin elasticity recovery guide for the 40s