Topical Vitamin C in DMSO vs Imiquimod for Basal Cell Carcinoma: The 2022 Trial
A small randomized trial in Idaho compared a vitamin C solution dissolved in DMSO with imiquimod cream on biopsy-confirmed, low-risk basal cell carcinomas. Here is what it found, what it could not show, and where DMSO comes in.
By Kymata Health Editorial Published Last checked
What this article covers
2 evidence profilesKey takeaways
From 8 sources- In a 2022 randomized trial, 25 patients with 29 biopsy-confirmed low-risk nodular or superficial basal cell carcinomas used either 30% ascorbic acid (vitamin C) in 95% DMSO twice daily for 8 weeks or imiquimod1.
- On biopsy after 8 weeks, 13 of 15 lesions (86.7%) had fully resolved with the vitamin C solution vs 8 of 14 (57.1%) with imiquimod, a significant difference (p < 0.05)1.
- At 12 weeks the vitamin C solution was non-inferior to imiquimod; it had fewer side effects, and at 30 months 70% of imiquimod patients had lighter skin patches left vs none with vitamin C1.
- It is one small trial at one centre, and a 2026 scoping review found only four small clinical studies of topical vitamin C for these skin lesions in total12.
- Basal cell carcinoma is diagnosed by biopsy and managed with a dermatologist; this trial enrolled only biopsy-confirmed low-risk lesions and checked every result with a second biopsy13.
The evidence, graded
Pulled from the trial tables in our evidence profiles. Grades follow our evidence-grading policy.
Graded findings
1 row- DGrade DBiopsy-confirmed clearance of low-risk basal cell carcinoma with ascorbic acid carried in DMSOImproved Post-treatment biopsy showed complete resolution in 13 of 15 lesions (86.7%) with ascorbic acid in DMSO vs 8 of 14 (57.1%) with imiquimod (p < 0.05); non-inferior at 12 weeks, with fewer adverse effects. Residual hypopigmentation at 30 months: 70% with imiquimod vs 0%.DMSO (dimethyl sulfoxide) · RCT · n=25 · 2022 · PMID 35217280
Safety at a glance
From our DMSO (dimethyl sulfoxide) evidence profilePublished interactions and cautions only. Each one is cited on our DMSO (dimethyl sulfoxide) evidence profile, with its own numbered sources.
Interactions
- Any medicine taken during DMSO therapy
- The Rimso-50 label says some data indicate DMSO potentiates other concomitantly administered medications and asks patients to tell their physician every medicine and dose they take.
- Other products on the same skin
- DMSO is a penetration enhancer, and the diclofenac-in-DMSO label says to wait until the treated area is completely dry before applying any of these to the same skin.
- Sulindac
- A 63-year-old man on sulindac 200 mg twice daily developed a severe sensorimotor peripheral neuropathy after starting 90% DMSO on his arms and legs, with incomplete recovery; a 1985 review notes neurotoxic interactions with sulindac have been reported.
- Dexrazoxane (for anthracycline extravasation)
- A 2009 Prescrire review says combining dexrazoxane with DMSO is contraindicated, based on animal studies.
Who should be careful
- Pregnancy
- High doses caused birth defects in several animal species; there are no adequate studies in pregnant women, and the Rimso-50 label says it should be used in pregnancy only if the benefit justifies the risk.
- Breastfeeding
- LactMed reports milk levels from one mother given 50 mL of 50% DMSO into the bladder: milk DMSO peaked at 34.5 mg/L at 5 hours, an estimated 0.45% of the mother's weight-adjusted dose; its metabolite and any effect on milk odour were not measured. Up to about 16% of a bladder dose is absorbed versus about 70% of an oral dose, so this does not apply to oral use. The label advises caution while nursing.
- Children
- Safety and effectiveness in children have not been established (Rimso-50 label).
- Eyes, nose and mouth
- Keep DMSO products out of the eyes and mucous membranes; if eye contact occurs, the diclofenac-in-DMSO label says to wash the eye with water or saline and see a doctor if irritation lasts more than an hour. High doses changed the lens in some animals, so the Rimso-50 label asks for eye exams before and during treatment; in 46 people examined after 12 weeks of 70% DMSO or controls, no lens changes were found.
Who ran the trial and what they asked
The trial was published in Biomedicine & Pharmacotherapy in April 2022 by Briant Burke and Jon-Eric Bailie, both listed at the Center for Biomedical Research, Inc., in Boise, Idaho1. Its stated aim was to compare a topical solution of 30% ascorbic acid in 95% dimethyl sulfoxide with topical imiquimod, which the authors describe as a standard and well-characterized topical treatment for basal cell carcinoma1.
The authors set the question against how common the cancer is: they cite an estimated 4.3 million basal cell carcinoma diagnoses a year and $4.8 billion in treatment costs1.
How the trial was set up
Twenty-five patients with 29 basal cell carcinomas, each confirmed by biopsy before entry, were randomly assigned to one of two arms1. Fifteen lesions received the ascorbic acid solution and 14 received imiquimod1. The lesions were low-risk nodular and superficial types1.
The vitamin C arm applied the solution twice daily for 8 weeks1. The main outcome was complete histologic resolution: a biopsy of each lesion site after the course, read for any remaining tumour1.
What we could not confirm: the abstract and the PubMed record do not say whether patients, clinicians or pathologists were blinded, how the allocation was concealed, how imiquimod was dosed, or how the study was funded1. We could not open the full text (the publisher's site blocked automated access), so these details are reported as not available rather than guessed.
The preparation: vitamin C dissolved in DMSO
The active solution was 30% ascorbic acid in 95% DMSO1. Ascorbic acid is vitamin C, and reviews of topical L-ascorbic acid note that its pH and concentration change how far it travels into skin and tissue6.
DMSO is the carrier. It is an established penetration enhancer in approved topical medicines, used to move both water-soluble and fat-soluble drugs through the skin5. Penetration enhancers work by loosening the packed lipids between skin cells, interacting with keratin and acting as a solvent for the drug inside the skin4. Our DMSO evidence profile explains the carrier role and what it means for handling, and the vitamin C evidence profile covers ascorbic acid itself.
What the trial found
At 8 weeks, post-treatment biopsies showed complete resolution in 13 of 15 lesions (86.7%) given ascorbic acid in DMSO and in 8 of 14 lesions (57.1%) given imiquimod; the difference was statistically significant (p < 0.05, chi-square)1. That is 29.6 percentage points more lesions cleared in the vitamin C arm1.
The authors report the vitamin C solution as superior at 8 weeks and non-inferior to imiquimod at 12 weeks1. Ascorbic acid was associated with fewer adverse effects than imiquimod1.
The longest follow-up looked at the skin left behind: at 30 months, 70% of patients in the imiquimod group had residual hypopigmentation (lighter patches) at the site, compared with 0% in the ascorbic acid group1.
Limitations
Size is the main limit: 29 lesions in 25 people means one or two lesions either way would move the percentages a lot, and the result needs repeating in a larger trial1. It was run at a single site, by two authors from one research company1.
The trial included only low-risk nodular and superficial lesions, so it says nothing about high-risk types, large tumours or lesions on the face where tissue sparing matters most1. Clearance was judged at 8 and 12 weeks; long-term recurrence is not reported in the abstract, which mentions only a 30-month skin-colour check1.
Blinding, allocation concealment, funding and conflicts of interest are not stated in the abstract or PubMed record, and we could not verify them from the full text1.
How it fits with other evidence
A 2026 scoping review of topical vitamin C for actinic keratoses and non-melanoma skin cancers found four studies in total: two randomized trials, one prospective observational study and one case report, covering 40 patients with actinic keratoses, 21 with basal cell carcinomas and 1 with squamous cell carcinoma2. It concluded that highly concentrated topical vitamin C may have some benefit for actinic keratoses and low-risk non-melanoma skin cancers, but that too few studies exist to support clinical recommendations2.
Other reports are smaller still: a 2021 case report described complete response of a cutaneous squamous cell carcinoma to a topical ascorbic acid solution7, and a 2021 review discussed how topical L-ascorbic acid formulations might be developed for these cancers6. A PubMed search on October 19, 2026 (ascorbic acid or vitamin C, basal cell carcinoma, topical or DMSO, plus the papers citing this trial) found no later randomized trial of ascorbic acid in DMSO for basal cell carcinoma2.
What this means in practice
Basal cell carcinoma is confirmed by biopsy, and standard first-line options for low-risk lesions are surgical excision or curettage and electrodesiccation, with Mohs surgery the standard for high-risk lesions3. A dermatologist decides which lesions are low risk and which options fit.
This trial is a promising early result inside that system, not outside it: every lesion was biopsy-confirmed before entry and biopsied again after treatment to check whether tumour remained1. Clearance was judged on histology, not on how the skin looked1.
DMSO itself has known effects worth knowing about: it causes a garlic-like taste and breath odour, and it carries whatever is on the skin or in the mixture through the skin84. Those properties are why the trial's preparation and setting matter, and why this article gives no recipe.
Quick answers
Common questions
6 answersDid vitamin C in DMSO beat imiquimod?
At 8 weeks, yes, in this one trial: 13 of 15 lesions cleared on biopsy vs 8 of 14 with imiquimod (p < 0.05). At 12 weeks the authors call it non-inferior1.
What concentration was used?
The solution was 30% ascorbic acid in 95% DMSO, applied twice daily for 8 weeks1.
Which basal cell carcinomas were included?
Only biopsy-confirmed low-risk nodular and superficial lesions; 29 lesions in 25 patients1.
Why is DMSO in the formula?
Has anyone repeated the trial?
We found no later randomized trial in PubMed as of October 2026, and a 2026 scoping review counted only four small clinical studies of topical vitamin C for these lesions2.
Who paid for the study?
The abstract and PubMed record carry no funding or conflict-of-interest statement, and the full text was not reachable for us to check. Both authors are listed at the Center for Biomedical Research, Inc., in Boise1.
Keep reading
Full evidence profiles
Every graded study, studied doses, interactions and safety- OtherDMSO (dimethyl sulfoxide)DMSO (dimethyl sulfoxide) is a small sulfur solvent that passes through skin and carries other molecules with it.BGrade B
- VitaminVitamin C (ascorbic acid vs buffered vs liposomal)Vitamin C (ascorbic acid) is a water-soluble vitamin and antioxidant needed to make collagen, some neurotransmitters and carnitine.BGrade B
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References
8 sources. Numbers in the text link here.
Sources cited in this article
8 sources- 1Randomized trial of topical ascorbic acid in DMSO versus imiquimod for the treatment of basal cell carcinomaBiomed Pharmacother, 2022 · PMID 35217280
- 2Topical Vitamin C in the Prevention and Treatment of Actinic Keratoses and Nonmelanoma Skin Cancers: A Systematic Scoping ReviewDermatol Surg, 2026 · PMID 41052296
- 3Beyond the scalpel: rare and experimental nonsurgical treatments for basal cell carcinomaDermatol Online J, 2026 · PMID 42246346
- 4Penetration enhancersAdv Drug Deliv Rev, 2004 · PMID 15019749
- 5Dimethyl sulfoxide: an effective penetration enhancer for topical administration of NSAIDsPhys Sportsmed, 2011 · PMID 22030943
- 6Topical L-Ascorbic Acid Formulation for a Better Management of Non-Melanoma Skin Cancer: Perspective for Treatment StrategiesPharmaceutics, 2021 · PMID 34452162
- 7Complete response of cutaneous SCC to topical treatment with ascorbic acid solution: A case reportClin Case Rep, 2021 · PMID 33768783
- 8RIMSO-50 (dimethyl sulfoxide) irrigant: prescribing informationDailyMed (NLM), 2021
DMSO is not a dietary supplement: it is a prescription drug or drug ingredient and is also sold as a solvent. This article summarizes published research; it is not a guide to using any product. Talk to your clinician or pharmacist, especially if you take prescription medicines. This page has no product or affiliate links.