Four different things get sold for cold sores, and they are not competing versions of the same product. One aims to shorten the outbreak, one disinfects, one soothes, and one covers. Judging them against each other only makes sense once you separate what each is actually for. Below is what the published evidence supports for each category, and what none of them do.
1. Topical antivirals: docosanol 10 percent
Docosanol 10 percent is the only over the counter topical the FDA has approved to shorten healing time in recurrent herpes labialis. It works at the point of cell entry, interfering with fusion between the viral envelope and the host cell membrane, rather than attacking the virus directly.
The evidence base is two randomised, placebo controlled trials covering 737 patients, reported in 2001. Median healing time was about 4.1 days versus 4.8 days on placebo. That is a real, statistically significant effect of roughly 18 hours, and it depends on starting during the prodrome, the tingle before anything visible appears. Start late and the measured advantage largely goes.
What it is for: modestly shortening an outbreak you have caught early. What it is not: a preventive, or a dramatic cure.
2. Antiseptics: benzalkonium chloride
Benzalkonium chloride is a quaternary ammonium antiseptic used across wound care and hand sanitising. Some cold sore products are built around it and marketed with fast resolution claims.
The regulatory position matters here. Benzalkonium chloride is classified as a topical antiseptic. It is not an FDA approved antiviral for herpes labialis. Antiseptics act on bacteria on the skin surface, which is a different job from interfering with a virus replicating inside cells. Published independent randomised evidence for shortening a cold sore is thin, and the strongest claims tend to trace back to manufacturer cited data rather than large independent trials.
What it is for: keeping a broken, weeping lesion clean and reducing secondary bacterial infection, which is a genuine benefit. What it is not: a demonstrated antiviral, on current public evidence.
3. Petrolatum and menthol balms
Conventional medicated lip balms combine an occlusive base such as petrolatum with counter irritants like menthol, camphor or phenol. They are widely used on cold sores because a cracking, splitting lesion is painful and an occlusive layer makes it less so.
These are symptomatic products. An occlusive barrier limits transepidermal water loss, which keeps the scab supple and reduces the painful re cracking that happens every time you speak or eat. That is worth something. It is not antiviral activity, and there is no good evidence this category shortens an outbreak.
One practical caution: menthol, camphor and phenol are counter irritants. On intact lips they are fine for most people. On a broken lesion, some people find they sting or aggravate. If a product stings meaningfully, that is a reason to stop, not to persist.
What it is for: comfort, moisture, less cracking. What it is not: a treatment that changes the course of the outbreak.
4. Hydrocolloid patches
Hydrocolloid patches are thin gel forming dressings, the same technology used on blisters and wounds. On a cold sore they do several useful things at once. They maintain a moist wound environment, which is well established in wound care as favourable for healing. They physically cover the lesion, which reduces picking and touching, and therefore reduces the chance of spreading virus to fingers, eyes or other people. They also conceal, which for many people is the actual problem.
Comparative studies of hydrocolloid cold sore patches against topical aciclovir cream have generally found similar healing outcomes, with patches rating better on cosmetic appearance and on reducing lesion trauma. The healing benefit appears to come from the dressing environment and from protection rather than antiviral action.
What it is for: covering, protecting, reducing spread, and looking better while it heals. What it is not: antiviral.
What none of them do
None of the four prevents the next outbreak, and none removes the virus. HSV 1 establishes latency in the trigeminal ganglion and stays for life. Everything above operates after reactivation has already begun.
That matters because the most reproducible trigger in the literature is one you can act on in advance. In a randomised, double blind trial of people with a history of sun induced recurrence, participants were exposed to experimental ultraviolet light. Among those using sunscreen, no recurrences occurred. In the placebo group, 71 percent recurred. Very little in this field produces a contrast that stark.
Lip tissue is especially exposed to this. The vermilion border has a thin stratum corneum, minimal sebaceous protection and very little melanin, so it absorbs a UV dose that the surrounding face tolerates. It is also the spot most people forget when applying sunscreen.
This is the category our own product sits in, so weigh it accordingly. A mineral SPF lip balm applied each morning and reapplied through sun exposure targets the trigger rather than the lesion. It does not treat an active cold sore and we do not claim it does. It reduces one well evidenced provocation, which is a different and earlier job.
Putting it together
- Caught it at the tingle: docosanol has the strongest over the counter evidence for shortening it, if applied immediately.
- Broken and weeping: keeping it clean is sensible. An antiseptic has a role here, just not as an antiviral.
- Cracking and sore: an occlusive balm helps comfort. Stop if a counter irritant stings.
- Visible and you need to get on with your day: a hydrocolloid patch covers it, cuts down touching and spreading, and heals comparably.
- Outbreaks that follow sun, snow or altitude: daily lip SPF is the preventive step with the most striking trial evidence.
- Frequent, severe, spreading or near the eye: see a doctor. Prescription oral antivirals are outside anything on a shop shelf, and eye involvement needs urgent attention.
Sources
- Sacks SL et al. Clinical efficacy of topical docosanol 10 percent cream for herpes simplex labialis: a multicenter, randomized, placebo controlled trial. Journal of the American Academy of Dermatology, 2001.
- US Food and Drug Administration. Over the counter monograph status for topical antiseptics, and docosanol 10 percent approval documentation.
- Rooney JF et al. Prevention of ultraviolet light induced herpes labialis by sunscreen. The Lancet, 1991.
- Karlsmark T et al. Randomized clinical study comparing a hydrocolloid patch with topical aciclovir cream in the treatment of recurrent herpes labialis. Journal of the European Academy of Dermatology and Venereology, 2008.
- Chi CC et al. Interventions for prevention of herpes simplex labialis (cold sores on the lips). Cochrane Database of Systematic Reviews, 2015.
Written by the Labisan Research Team and edited by Alex, founder. Labisan has produced protective lip care in Austria since 1931. This article summarises published literature and cites its sources. It has not been reviewed by a licensed clinician, and it is not medical advice. Last updated 9 August 2026.
