Borax substitute (sodium sesquicarbonate) does most of what borax does — cuts grease, lifts limescale, boosts your wash — without the toxicity warnings that come with actual borax. This guide covers the exact ratios, the jobs it's genuinely good at, and the mistakes that waste a tub of it.
- Mix 1-2 tbsp of borax substitute per litre of warm water for an all-purpose cleaning solution in 2026.
- Sodium sesquicarbonate handles grease, limescale and laundry boosting — Regn's 500g tub costs £1.58.
- Never mix borax substitute with vinegar or acidic cleaners; it neutralises the alkalinity that makes it work.
- For septic tanks or greywater systems, check the label first — most sodium sesquicarbonate is safe but concentration matters.
Why this matters
Borax itself carries a reproductive toxicity warning in the EU and UK, which is why most household cleaning ranges phased it out years ago. Sodium sesquicarbonate — the actual chemical name behind "borax substitute" — is a naturally occurring mineral compound that does the same alkaline heavy lifting: cutting grease, softening water, lifting stains, without the same hazard label.
The catch is that most people buy a tub, use one tablespoon in the wrong place, get a lukewarm result, and shelve it. Used correctly across the eco-friendly cleaning products for kitchens you already own — a spray bottle, a scrub brush, hot water — borax substitute earns its cupboard space back within a month.
What you'll need
- Borax substitute (sodium sesquicarbonate), 500g or 750g tub
- Warm water — not boiling, not cold
- A refillable cleaning spray bottle for the diluted solution
- A microfibre cloth or scrub brush for stubborn grime
- Measuring spoons (a standard tablespoon is close enough)
- Rubber gloves if you have sensitive skin — sodium sesquicarbonate is mild but still alkaline
The steps
1. Patch-test on an inconspicuous spot
Before you use borax substitute on a new surface — painted wood, sealed stone, coloured grout — dab a small mixed patch and leave it 10 minutes. Sodium sesquicarbonate is alkaline enough to dull some waxed or oiled finishes over repeated use. This step takes two minutes and saves a ruined worktop.
2. Mix your base solution
Dissolve 1-2 tablespoons of borax substitute per litre of warm water. Warm water matters here — cold water leaves undissolved granules that streak glass and leave a gritty residue on hard floors. Stir until the water goes slightly cloudy and clear, not chalky. Pour into your spray bottle for everyday use, or keep it in a jug for soaking jobs.
3. Cut grease in the kitchen
Spray the solution directly onto hob splashback, oven door glass, or greasy extractor filters and leave for five minutes before wiping. The alkalinity breaks down fat molecules the way washing-up liquid alone can't manage on baked-on residue. For genuinely stubborn buildup, bump the ratio to 3 tablespoons per litre and let it sit 15 minutes. Expect the grease to lift into a wipeable film rather than needing a scouring pad.
4. Boost your laundry wash
Add 1-2 tablespoons of borax substitute directly to the drum alongside your usual laundry detergent sheets — it softens hard water and helps whites stay whiter over repeated 2026 washes. It's not a standalone detergent; it's a booster. Skip it on wool and silk cycles, where the alkalinity is too aggressive for delicate fibres.
5. Descale and scrub the bathroom
Make a paste with 2 tablespoons of borax substitute and just enough water to bind it, then scrub directly onto limescale around taps and shower screens. Leave 10 minutes, then rinse. On stubborn tidemarks, a second application usually finishes the job — sodium sesquicarbonate works cumulatively rather than in one aggressive hit like a bleach-based descaler.
6. Freshen and unblock drains
Pour half a cup of dry borax substitute straight down a slow kitchen or bathroom drain, followed by a kettle of hot (not boiling) water. It breaks down grease-based clogs and neutralises drain odour within a few hours. For anything more solid than a grease build-up, you'll need mechanical clearing first — see the troubleshooting section below.
7. Store it dry and sealed
Sodium sesquicarbonate clumps if it picks up moisture from bathroom or under-sink storage. Keep the tub sealed and somewhere dry — a kitchen cupboard, not under the sink next to a leaking pipe. A clumped tub still works, but you'll need to crush it back to powder before it dissolves evenly.
Troubleshooting
Solution looks cloudy and won't clear — you've used cold water or too much powder. Reheat slightly and stir longer; sodium sesquicarbonate dissolves fully around 30-40°C.
Residue left on glass or mirrors — you're using too strong a mix for glass. Drop to 1 tablespoon per litre and buff dry with a cloth instead of air-drying.
No improvement on a slow drain after 24 hours — the blockage is likely solid (hair, food debris), not grease. A natural approach that goes further is the drain unblocker method for kitchen sinks, which combines mechanical clearing with a chemical soak.
Fabric feels stiff after laundry boosting — you've overdosed the drum. Halve the amount next wash and add an extra rinse cycle.
Paste dries too fast to scrub — bathroom air is warm or the paste is too thin. Mix a slightly thicker paste and work in smaller sections.
Powder has clumped in the tub — moisture got in. Break it up with the back of a spoon; it still dissolves fine once broken down.
Tools and resources
- Refillable cleaning spray bottle in recycled aluminium — for diluted borax substitute solution
- A 7-piece kitchen cleaning brush set or coconut scourer for scrubbing paste jobs
- Toilet cleaning tablets with limescale remover for between-scrub maintenance
- A dedicated laundry booster routine — see the guide on making a natural cleaning paste with washing soda if you want a second alkaline cleaner in rotation alongside borax substitute
What to do next
Once borax substitute is part of your weekly routine, the next upgrade is swapping the rest of the cupboard — dishwasher tablets, multi-surface sprays, drain cleaners — for equally low-toxicity options. Regn stocks the full range if you want to keep the whole kitchen and bathroom on the same non-toxic standard through 2026 and beyond.
FAQ
How do you use borax substitute for cleaning?
Dissolve 1-2 tablespoons of borax substitute in a litre of warm water for an all-purpose spray, or make a thicker paste for scrubbing limescale and grease. Always use warm water to avoid gritty residue.
Is borax substitute the same as borax?
No. Borax substitute is sodium sesquicarbonate, a different mineral compound that mimics borax's cleaning power without its reproductive toxicity warning. It's milder but works similarly on grease and limescale.
Can you use borax substitute in the washing machine?
Yes, add 1-2 tablespoons directly to the drum alongside your usual detergent to soften hard water and boost whites. Skip it on wool or silk cycles where the alkalinity is too harsh.
Does borax substitute unblock drains?
It clears grease-based clogs when combined with hot water, but it won't shift solid blockages like hair or food debris. For those, mechanical clearing plus a chemical soak works better.
How much does borax substitute cost in 2026?
A 500g tub costs around £1.58 and a 750g tub around £4.16 as of 2026, making it one of the cheaper multi-purpose cleaners per wash.
Is borax substitute safe for septic tanks?
Most sodium sesquicarbonate products are safe for septic systems in normal doses, but always check the specific product label since concentration varies by brand.
Can you mix borax substitute with vinegar?
Don't. Vinegar is acidic and borax substitute is alkaline, so mixing them neutralises both and cancels out the cleaning power you're trying to get.
What surfaces should you avoid using borax substitute on?
Avoid waxed wood, oiled worktops and some sealed natural stone, where repeated alkaline contact can dull the finish over time. Patch-test any new surface first.
One last thing
The single biggest mistake with borax substitute isn't dosage — it's water temperature. Cold water leaves undissolved granules behind on every surface, which is the reason most people give up on it after one try and assume it "doesn't work like borax." Warm water first, every time, and the results match what people expect from the real thing.
