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High strength vs medium threadlocker

Updated: October 2026

You are choosing a red, blue, green or purple bottle. High strength vs medium threadlocker is that decision. Choose high strength only when you will not undo the joint with hand tools. Choose medium, or low on a small thread, when you will. Cap colour is not one code. Prices and fill stay on the [buying guide](/hub/cutting-tools/threadlocker-high-strength/sub/threadlocker-high-strength-buying-guide). Who each bottle is for is on the [best high-strength threadlocker](/hub/cutting-tools/threadlocker-high-strength/sub/threadlocker-high-strength-best) page. Assembly is [how to apply threadlocker](/hub/cutting-tools/threadlocker-high-strength/sub/threadlocker-high-strength-how-to-apply). The listings are on the [high-strength threadlocker comparison](/hub/cutting-tools/threadlocker-high-strength). There was no lab test.

You are choosing a red, blue, green or purple bottle. High strength vs medium threadlocker is that decision. Choose high strength only when you will not undo the joint with hand tools.

Our top picks

Loctite Loctite 270 50 ml

Best overall

Loctite Loctite 270 50 ml
8.4/10about £11.50
View offer
Realth Realth 10 ml × 3

Alternative

Realth Realth 10 ml × 3
6.5/10about £8.99
View offer
sitarcmin sitarcmin 50 ml + 50 ml

Best value

sitarcmin sitarcmin 50 ml + 50 ml
8.1/10about £8.99
View offer
On this page
  1. 1.High, medium or low comes before the cap colour
  2. 2.Red, blue and green are not one code
  3. 3.Thread size is guidance, not a law
  4. 4.What that means for these eight listings

High, medium or low comes before the cap colour

The question is whether you will open the joint. Henkel’s UK chooser puts low and medium grades on fasteners you remove with hand tools, and high strength on a joint you do not plan to open. High strength may need heat. This page does not pick a removal temperature, because the published heats do not agree. Use medium for a cover you will see again. Use low strength on a small screw you must not damage, which is where Henkel places 222. Use high strength for a stud or a pump bolt that should stay shut. Buying high on a bolt you will undo later is how a head gets rounded.

Red, blue and green are not one code

On the unbranded packs in this set, the usual habit is red for permanent and blue for a joint you can undo. Loctite’s UK consumer guide uses the same habit. Henkel’s high-strength grade here does not. Loctite 270 is green. If you assume green means light and red means permanent, you will misread the only named high-strength bottle in the set. Green is also the colour of wicking grade 290, which is not one of these eight listings.
Loctite Loctite 270 50 ml

Testsieger

Loctite Loctite 270 50 ml
8.4/10about £11.50
View offer

Thread size is guidance, not a law

Henkel’s UK chooser, as guidance rather than a regulation, maps Loctite 222, purple and low, to small threads up to M12, Loctite 243, blue and medium, up to M18, and Loctite 270, green and high strength, up to M20. You can put a high-strength grade on a smaller bolt. Removal then gets harder, because you have less head for a spanner. That is not a ban, and it is not a measurement from this desk. An M6 cover screw you will see at every oil change is a poor place for a permanent grade. Do not import a chart that calls red medium and purple high. The 33 N·m figure does not move onto 243 or onto a red bottle.

What that means for these eight listings

One kept listing is the named green high-strength grade: Loctite 270, ASIN B0068NKI5A, 50 ml, and the only one with that published torque. The twin packs put a high-strength bottle beside a medium one: Nanoxa, sitarcmin, Abnaok and GOLDEROC. Realth adds a purple low-strength bottle. None of those red bottles inherits 270’s torque or NSF P1 123006. Abnaok’s title prints 243 and 271. The brand is Abnaok, not Henkel. If the label is in a language you cannot read, you cannot know which bottle is permanent, which is what one UK reviewer reported. If you already know the bolt has to come apart with a spanner, buy medium.

Common questions

If I will undo this bolt with a spanner, do I want high strength or medium?
Medium. High strength is for a joint you do not plan to open, and Henkel says it may need heat. Low and medium are the grades that chooser puts on hand tools. If the thread is small and you are worried about the head, low strength is the gentler of those two.
Is red always the permanent grade, and is green always high strength?
No. In this set, unbranded high-strength bottles are generally red, and Loctite’s consumer guide also calls red the high-strength colour. Loctite 270, the named high-strength grade here, is green. Green is also used for wicking grade 290, which is not in these eight listings. Read high, medium or low on the title. The dye is not a shared code.
What is the difference between Loctite 222, 243 and 270?
On Henkel’s UK chooser, 222 is purple and low, up to M12. 243 is blue and medium, up to M18, for a joint you undo with hand tools. 270 is green and high strength, up to M20, for a joint you do not plan to open. Those sizes are guidance, not a law.
Can I treat an unbranded bottle printed 243 or 271 as Henkel?
No. Abnaok’s title uses 243 and 271, and the manufacturer is Abnaok. sitarcmin’s model line says 242/262, and the manufacturer is WEIKESITA. Printed numbers do not transfer Henkel’s torque, the NSF registration or the note about passive metals. If the label does not say high or medium in words you can check, leave it.
Is green Loctite 270 the same product as green Loctite 290?
No. Loctite 270 is the high-strength grade you apply as you assemble, then leave. Loctite 290 is Henkel’s wicking grade for a fastener that is already made up. Both can appear green in Henkel’s materials. 290 is not one of the eight listings here. Do not buy green 270 expecting it to wick into an assembled thread.
Will high strength on a small bolt make it harder to remove later?
It can. Henkel’s chooser aims 270 at larger threads, up to M20, and aims the low grade at small threads up to M12. A permanent film on an M5 or M6 screw leaves you less head when you need it apart. If you will remove a small screw, use low or medium strength.
Does any bottle here except Loctite 270 publish a breakaway torque?
No. The 33 N·m breakaway and prevail figure is on Henkel’s data sheet for Loctite 270, ISO 10964, M10 steel, 24 hours at 22 °C. It is not a figure for the red bottles or for a title that borrows 271. If a listing publishes no torque, this comparison does not invent one from the cap colour.

Related pages

How to remove threadlocker

High-strength threadlocker

Best high strength threadlocker: top pick and value

High strength threadlocker: metal, fill, and torque

How to apply threadlocker before you load the joint

Sources

Sources from the research digest. amazon.co.uk listings in this comparison were read on 15 October 2026. We did not run a laboratory test.

  1. Henkel UK, LOCTITE 270 (retrieved 15 October 2026)
  2. Henkel TDS, LOCTITE 270, November 2024 (retrieved 15 October 2026)
  3. Henkel UK, choosing a threadlocker (retrieved 15 October 2026)
  4. Henkel UK, blue, green and purple threadlockers (retrieved 15 October 2026)
  5. Loctite consumer UK, how threadlocker works (retrieved 15 October 2026)
  6. HSE, COSHH basics (retrieved 15 October 2026)
  7. HSE, GB CLP (retrieved 15 October 2026)
  8. Consumer Rights Act 2015, section 9 (retrieved 15 October 2026)