Zinc, White Cast and SPF Claims: An Honest Guide to Mineral Sun Balm

I am going to start with the part most brands would bury at the bottom, because it is the part that matters most.

The Sun Balm has not been SPF tested. Until it has, please do not use it as your sun protection. It is a mineral-rich barrier balm, and I would rather lose the sale than have someone burn because I was vague about that.

What this balm is, and what it is not

It contains 15% non-nano zinc oxide in a base of raw plant butters and oils. Zinc oxide is a genuine mineral UV filter, and it is the filter most often recommended for reactive skin.

But the percentage of zinc in a formula does not tell you the SPF. How evenly the zinc is dispersed, how thickly the product is applied, and how it behaves as it sits on skin all change the result, sometimes dramatically. A balm containing 15% zinc could test anywhere across a wide range, and the only way to know is to have it tested properly.

So here is the honest position. If you are going to be out in strong sun, wear a tested sunscreen with a stated SPF and UVA rating. Use this balm for what it is actually good at, which is supporting a barrier that struggles in heat.

Why the testing has not happened yet, and what it costs

People assume this is something I could get done in a fortnight if I cared enough. I want to explain why it is not.

SPF testing is done in vivo, on human volunteers, under a standardised international method. UVA protection is assessed separately, with its own test. Water resistance, if you want to claim it, is another one again.

It also runs in stages, which is why I cannot give you one figure. What you end up spending depends on how the early stages go and how far up the levels you need to take it. What I can tell you is that it is thousands rather than hundreds, that the cost is per formulation rather than per brand, and that changing the base oils means starting again from the beginning.

There is also a second formula I have been working on. It is genuinely different to this one and suits different skin, and if I keep both then both need testing, which doubles the bill rather than splitting it.

For a business where I make, pour, label and pack everything myself, that is not a line item. It is a serious chunk of a year's profit, committed upfront, before a single tested pot is sold.

It is happening. I have been putting money aside for it, because the intention has always been to bring this back properly tested rather than keep selling it with a caveat forever. When the results come in, the number goes on the label and I will publish it here, whatever it says.

Why sensitive skin has a harder time in warm weather

Heat, sweat, salt water, chlorine and sun exposure all pull at the skin barrier in different ways. Sweat itself is mildly irritating to compromised skin, and the salt left behind as it evaporates is more so. Heat increases blood flow to the skin, which is why redness looks worse in summer even when nothing has actually flared.

The result is skin that is drier and more reactive than usual, right at the point in the year when you are asking it to tolerate more products than usual. That is the squeeze, and it catches people out every summer.

When skin gets to that stage, adding more is rarely the answer. The Barrier Repair Balm exists for exactly that stretch, and if your skin is genuinely unhappy it is the better starting point of the two.

Why some people find mineral filters more comfortable

I want to be fair here, because there is a lot of nonsense written about this.

Organic UV filters, the ones usually called chemical filters, are extensively tested and work well for the overwhelming majority of people. A sunscreen you will actually reapply is worth more than a theoretically perfect one sitting unused in a drawer. I am not going to tell you they are dangerous, because the evidence does not support that.

What is true is that they work by absorbing UV energy and releasing it as heat, and a small number of people with very reactive skin find that uncomfortable, particularly in already-hot conditions. Some also react to specific filters, or to the fragrance and alcohol carriers that often come with them. Stinging around the eyes when you sweat is a common complaint.

Mineral filters like zinc oxide sit on the surface and scatter and absorb UV without that same heat sensation. For some people that is the difference between wearing sun protection and skipping it. If that is you, a tested mineral sunscreen is what you want.

The raspberry seed oil myth, while we are being honest

You will see it claimed that red raspberry seed oil has a natural SPF of 28 to 50, and you will see it repeated by natural skincare brands who should know better.

It traces back to a single small laboratory study from 2000, measured in a way that does not reflect how a product performs on skin. It has never been replicated to any standard that would allow an SPF claim. Carrot seed oil gets the same treatment and the same problem applies.

Raspberry seed oil is in my balm because it is high in antioxidants and behaves beautifully in a formula. It is not in there as a sun filter, and I will not pretend otherwise. Any brand telling you a plant oil is your sun protection is selling you a burn.

What is actually in it

Non-nano zinc oxide at 15%. Non-nano means the particles are larger than 100 nanometres, so they stay on the skin surface rather than passing through it. It is also what gives the balm its white cast, which I have not tried to engineer out.

Organic shea and cocoa butter. The structure of the balm and the bulk of the conditioning.

Jojoba and avocado oil. Jojoba is close to skin's own sebum and absorbs readily. Avocado is heavier and richer, and holds the balm together through warm weather better than lighter oils do.

Raspberry seed and rosehip oil. Both high in antioxidants and essential fatty acids. Antioxidants are worth having on skin that is dealing with UV exposure, though they support rather than replace actual protection.

Chamomile and lavender. Calming, and the reason it smells the way it does rather than of nothing.

Applying it, and the white cast question

Let me deal with the white cast honestly first, because a lot of brands promise it away and then people are disappointed.

Zinc oxide is a white mineral sitting on the surface of your skin. It will show, particularly on deeper skin tones. Good technique reduces it. Nothing eliminates it. Anyone claiming their mineral product disappears entirely is either using nano particles or is not being straight with you.

What genuinely helps:

1. Warm it first. A small amount between your palms for a few seconds until the butters melt and it turns from solid to oil. Applying it cold and solid is where the streaking and the thick chalky look come from.
2. Dot, then spread. Small dots across forehead, cheeks, nose and chin, then blend outwards. Trying to spread one big blob never works evenly.
3. Apply to slightly damp skin. It glides much further, so you get better coverage with less product.
4. Give it a few minutes. It settles considerably as it warms to skin temperature, so judge it after five minutes rather than immediately.

One thing I would not do is apply it thinly to avoid the cast. With any mineral product, thin application means uneven coverage, and there is no version of this where looking better is worth being less covered.

The bits people forget are the tops of the ears, the back of the neck, and the parting in your hair. Those are the places I have seen sun damage most often.

Taking it off again

Mineral products sit on the surface, which is exactly what they are supposed to do, and it means a splash of water will not shift them. Zinc plus rich plant butters needs something that dissolves oil.

The Cleansing Oil does it in one pass, massaged into dry skin and removed with a warm damp cloth. Oil dissolves oil, so it lifts the balm off without the stripped feeling you get from a foaming cleanser fighting a zinc layer.

Then a balm afterwards while your skin is still slightly damp. A day of sun, wind and salt takes more out of your barrier than people realise.

How I would actually use it

A morning that suits reactive skin, in order.

1. Cleanse with the Cleansing Oil. Cleansing is where most routines do their damage, and an oil lifts everything off without the tight, stripped feeling afterwards.
2. Hydrate with the Facial Toner. Aloe and rose water, and it sits under the balm particularly well. A balm spreads far more easily over slightly damp skin than dry skin, so you use less and it goes on more evenly.
3. Seal with the Sun Balm. A generous layer, warmed between your fingers first.
4. Then your tested sunscreen, if you are going to be out in it. On top, generously, and reapplied. This step is not optional and the balm does not replace it.

For days that are mostly indoors, school runs and a walk, the first three steps are what most people with reactive skin actually need. For a beach day, a garden all afternoon, or anything at altitude, wear proper sunscreen.

After a day in the sun

Cool the skin down before you put anything on it. A cool shower, or a cool damp flannel held against the warm areas for a few minutes. Skin that is still radiating heat does not want a rich balm sealed over the top of it, because that traps the heat in and makes it feel worse rather than better. Wait until it feels properly cool to the touch.

Once it is, the Hydrate & Calm Balm is the one I reach for. It is the only balm I make with a high percentage of aloe vera leaf juice in it, and that changes how it feels considerably. It goes on lighter and cooler than the rest of the range, which on skin that has had too much sun matters far more than richness does.

Aloe has been the after sun ingredient for a very long time, and mostly for good reason. It is largely water, it feels cool going on, and it sits comfortably on skin that does not particularly want to be touched. It is also why this is the balm parents keep coming back to, because it is the one that goes on easily when someone is already uncomfortable and not in the mood to be creamed.

One honest limit. This is for skin that is warm, tight and uncomfortable. If skin is blistered, if a child has burned badly, or if anyone is feeling shivery, sick or unwell after sun exposure, that is a pharmacist or a GP rather than a balm. Please do not try to manage a real burn with skincare.

The award

The Sun Balm took Bronze at the Free From Skincare Awards 2025, which judges products formulated without common irritants and aimed at sensitive and allergy-prone skin. It is judged partly by people with reactive skin actually using the products, which is the part that meant something to me.

Frequently Asked Questions

Can I use the Sun Balm instead of sunscreen?
No. It has not been SPF tested, so there is no verified level of protection to rely on. Wear a tested sunscreen for sun exposure and use this balm for barrier support.

Does 15% zinc oxide mean it is roughly SPF 15?
No, and this is a common misunderstanding. The percentage of a UV filter does not translate to an SPF number. Dispersion, application thickness and the behaviour of the base all affect the result, which is why testing exists.

Is it suitable for babies or young children in the sun?
Not as sun protection, no. Babies under six months should be kept out of direct sun altogether, and older babies and children need a tested sunscreen with a stated SPF alongside shade and covering clothing. This balm has no verified protection level, so please do not rely on it for a child outdoors.

Will it leave a white cast?
Yes, to some degree, and more so on deeper skin tones. Non-nano zinc oxide sits on the skin surface and that is what causes it. Warming the balm first, dotting and spreading rather than rubbing one blob, and applying to slightly damp skin all reduce it. Nothing removes it entirely, and applying it thinly to avoid it means uneven coverage.

What does non-nano zinc oxide mean?
That the particles are larger than 100 nanometres, so they sit on the skin surface rather than passing through it. It is the reason for the white cast, and it is a deliberate choice rather than a shortcoming.

Is it reef safe?
Reef safe is not a regulated term, so I am cautious about it. What I can say is that it contains none of the chemical filters most associated with coral bleaching, and that mineral filters are generally considered lower risk. I would not claim it is proven harmless to marine life, because nobody can honestly claim that.

How do I remove it?
An oil cleanser. Mineral products sit on the surface by design, so water alone will not shift zinc combined with plant butters. Oil dissolves oil and takes it off in one pass.

How long does a jar last?
It varies with how much of you is being covered, but the formula is concentrated and you need far less than a lotion. Keep it out of direct sunlight and away from heat, and it will keep well.

When will the SPF testing be done?
It is planned and being saved for. When the results come back, the figure goes on the label and I will publish it here regardless of what it says.

Why is SPF testing so expensive for a small brand?
It is carried out in vivo on human volunteers under a standardised international method, with UVA protection tested separately. It also runs in stages, so the final cost depends on how far you need to take it. It is thousands rather than hundreds, it is priced per formulation rather than per brand, and any change to the formula means starting again.

What should I use after too much sun?
Cool the skin first, with a cool shower or a damp flannel, and only apply anything once it feels cool to the touch. After that, the Hydrate & Calm Balm is the one I would use, because the aloe content makes it lighter and cooler on skin than the other balms. If there is blistering, or anyone feels unwell, see a pharmacist or GP instead.

Does raspberry seed oil provide sun protection?
No. That claim comes from one small laboratory study that has never been replicated to a standard that would support an SPF claim. It is a good antioxidant oil and nothing more.

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The Sun Balm is here, described exactly as it is. If you have questions about whether it suits your skin, message me. I would rather have that conversation than have you buy the wrong thing.