Buy aciclovir cream 5%: the one that works if you catch it early

Aciclovir cream 5% is one of only three products in this catalogue that can be bought without a prescription, and it is the cheapest thing here — from $15.50 a tube. It is also the one whose usefulness depends almost entirely on timing. Applied at the tingle, before anything is visible, it can shorten a cold sore by a day or so. Applied once the blister has formed, it does very little, because by then viral replication has already peaked and what remains is healing.

How to use it so it earns its place

Five times a day, roughly every four hours during waking hours, for five days — extended to ten if the lesion has not healed. Dab a small amount onto the affected area and a little beyond its edge; the lesion spreads outward and treating only the visible part treats yesterday's problem.

Wash your hands before and after. Use a cotton bud rather than a finger if you can, and never share the tube. Transferring the virus to an eye causes herpetic keratitis, which is a sight-threatening infection and not something to risk for the sake of convenience.

Prices

A 5 g tube covers several episodes. Buying two is reasonable if you get recurrent cold sores: the whole point is having one within reach when the tingle starts, and a tube in a drawer at home is useless at the office.

What it will not treat

Genital herpes. Topical aciclovir does not penetrate deeply enough to affect genital lesions meaningfully, and the trials that tested it there were unimpressive. Genital herpes is treated with oral aciclovir, either episodically or as suppression, and that requires a prescription.

It also will not treat shingles, which needs high-dose oral antiviral started within seventy-two hours of the rash, nor herpetic eye infection, which is an ophthalmic emergency requiring specific eye preparations and specialist assessment. Getting any of these wrong by reaching for the cream wastes the window in which treatment actually works.

Why cold sores come back

Herpes simplex type 1 remains in the trigeminal ganglion for life after a first infection, usually acquired in childhood. Reactivation is triggered by ultraviolet light, fever, physical stress, menstruation, dental work and fatigue — which is why cold sores cluster around holidays, illnesses and exams.

The practical consequence: if sunlight is your trigger, a high-SPF lip balm does more than any cream to prevent episodes, and prevention beats treatment on a condition where the treatment window is measured in hours. People with very frequent recurrences — more than six a year — are candidates for oral suppressive therapy rather than repeated topical treatment.

Side effects and precautions

Mild transient burning or stinging on application is common and not a reason to stop. Local dryness or flaking occurs. Genuine contact dermatitis is uncommon and is usually a reaction to propylene glycol in the base rather than to aciclovir itself.

It is suitable for use in pregnancy and breastfeeding, where systemic absorption from topical application is negligible. Avoid mucous membranes — inside the mouth, the eyes, the genitals. Someone who is significantly immunosuppressed should not be self-treating herpes lesions topically; they need oral treatment and medical review, because lesions in that setting can become extensive.

Living with recurrent cold sores

A visible lesion on the face at the wrong moment causes a disproportionate amount of avoidance — of photographs, of meetings, of kissing, of sex. That is worth naming rather than dismissing, particularly where it has turned into a pattern of withdrawal from intimacy that outlasts the lesion. Where that is happening, the problem has stopped being dermatological. Clinical sexology covers it, and the first consultation at this studio is free. Other antivirals are listed under antivirals.

Recognising the prodrome

Most people who get recurrent cold sores can feel one coming, and the sensation is consistent for each individual: tingling, itching, burning or a tight feeling at the same spot, typically six to forty-eight hours before anything is visible. That interval is the entire therapeutic window for a topical antiviral.

Learning your own prodrome is worth doing deliberately. People who treat at the prodrome shorten episodes; people who treat at the blister mostly do not. If you cannot reliably identify it, the realistic plan is sun protection and prevention rather than a tube that will always be applied too late.

Preventing rather than treating

Ultraviolet light is the commonest identifiable trigger, and lip balm with SPF 30 or higher used routinely prevents more episodes than any cream treats. Skiing and beach holidays are the classic settings, because reflected light doubles the exposure and nobody puts sunscreen on their lips.

Other recognised triggers: fever and intercurrent illness, physical or emotional stress, menstruation, dental work and fatigue. Not all are avoidable, and knowing which one is yours changes what you do about it — a person whose outbreaks follow dental appointments can start treatment prophylactically, which is worth discussing with a prescriber.

Anyone getting more than six episodes a year is a candidate for oral suppressive therapy rather than repeated topical treatment, and that is a conversation rather than a self-management decision.

Avoiding transmission while a lesion is active

Herpes simplex is transmitted by direct contact with the lesion or with virus in saliva. During an active episode: no kissing, no sharing cups, cutlery, towels or lip products, and careful hand hygiene after touching the area — transferring the virus to the eye causes herpetic keratitis, a sight-threatening infection.

Oral-genital contact during an active cold sore transmits HSV-1 to the genitals, which is now a substantial proportion of new genital herpes diagnoses in several countries. That is worth stating plainly because almost nobody is told it, and it is the piece of information most likely to prevent a diagnosis that will cause real distress.

Storage

Below 25 °C with the cap closed. Do not refrigerate unless the carton says so. Discard the tube after the in-use period stated on the pack once opened, typically a few months, and do not keep a tube that has been open for a year against the next episode.

Never share a tube. The nozzle contacts an active lesion and carries virus to the next user.

When a cold sore is not a cold sore

Lesions that do not heal within two weeks, that recur in exactly the same spot without the usual prodrome, that bleed, or that spread beyond the lip border deserve a look rather than another tube. Impetigo, angular cheilitis and in rare cases a skin cancer all get treated as cold sores for months.

Any lesion near or involving the eye is urgent rather than routine — herpetic keratitis threatens sight and needs ophthalmic treatment rather than a skin cream.

Using it alongside oral treatment

For someone on oral suppressive therapy who still gets occasional breakthrough lesions, the cream is a reasonable addition at the prodrome. It does not interact with oral aciclovir and the systemic absorption from topical use is negligible.

What it does not do is substitute for oral treatment in genital herpes or shingles, where topical application has been tested and found inadequate.

Questions

Does it need a prescription?

No. It is one of three over-the-counter products in this catalogue and goes straight into the basket.

How much difference does it actually make?

Roughly half a day to a day off the episode when started at the prodrome. That is modest, and it is honest — claims of dramatic benefit are not supported by the trials.

Can I use it under makeup?

Let it absorb first. Applying makeup over an active lesion risks contaminating the applicator, which then reintroduces the virus at the next use.

Is there anything better?

For frequent recurrences, oral suppressive therapy outperforms any topical treatment. For occasional ones, early application plus sun protection is the realistic best.

The label these figures come from

Efficacy, dosing and precautions follow the FDA prescribing information for topical aciclovir and the herpes simplex guidance published by the US Centers for Disease Control and Prevention.